The present invention pertains to specific peptides obtainable from cocoa beans and giving rise to a particular and distinct savor when subjected to a Maillard reaction with reducing sugars. In particular the present invention pertains to the use of such specific peptides for the preparation of a chocolate flavor, specifically a cocoa and a caramel flavor, a floral or more specifically, a bonbon flavor, a bready flavor, or a roasted or meaty flavor.
The typical cocoa flavor emanates during processing of cocoa beans which processing comprises fermentation, drying and roasting.
During fermentation, the cocoa seed proteins are degraded by microbiological and enzymatic processes to yield mainly hydrophilic peptides and hydrophobic amino acids, which serve as flavor precursors for the unique chocolate flavor. The cocoa proteolytic system involved in these processes is highly efficient. The endogenous proteolytic activity in cocoa is represented by endoproteases, amino-peptidases and carboxypeptidases, which in concert have the capability to hydrolyze intact protein to single amino acids and oligopeptides of different length.
During roasting, various chemical reactions occur, such as Maillard-type reactions and thermal degradation reactions (decarboxylations, deaminations, oxidations etc.). The Maillard reaction involving peptides, amino acids and reducing sugars generates compounds that are deemed to eventually contribute to the final cocoa/chocolate flavor.
In the recent past, more and more evidence has been brought up that the size of the peptides and their amino acid contents/sequence play an important role in flavor development. The amino acid pool in non-roasted and roasted fermented cocoa has been investigated and certain hydrophobic amino acids have been found to be implicated in the generation of cocoa flavor (Seiki, Rev. Int. Choc. 28 (1973) 38–42). However, the identification of naturally occurring peptides is quite difficult due to the presence of free amino acids and polyphenols in the cocoa beans. As a consequence, little is known in the art so far about the nature of the short-chain peptides that are present in the cocoa peptide pool.
Several attempts have been made to artificially produce cocoa flavor. One such attempt comprises subjecting acetone dried powder prepared from unfermented ripe cocoa beans to an autolysis at a pH of 5.2 followed by roasting in the presence of reducing sugars (Voigt et al., Food Chem. 49 (1994), 173–180). Mohr et al. report in Fette Seifen Anstriche 73 (1971), 515–521, about the isolation of a peptide fraction showing potential for chocolate flavor formation. Moreover, Voigt et al. report in several articles in Food Chem. 51 (1994), 7–14; 177–184; and 197–205, about the production of a peptide-enriched pool of flavor precursors using purified storage proteins and endogenous cocoa proteolytic system, which precursors upon thermal reaction with reducing sugars resulted in a chocolate like flavor.
It had also been recognized that thermal reactions of a mixture of fructose/glucose, and hydrophobic amino acids under low water activity medium, e.g. glycerol or propylene glycol etc., gives rise to a chocolate-like aroma. Using this type of reaction flavor as a base and combining it with certain top notes, most prominent vanilla, chocolate-like flavor concentrates could be produced. However, due to the complex nature of these reactions, a clean and well-balanced chocolate flavor concentrate is difficult to obtain, also creating the problem of providing a constant quality.
Pertinent to the development of process reaction flavors for chocolate, Schnermann et al. report in “Evaluation of key odorants in milk chocolate and cocoa mass by aroma extract dilution analyses” (J. Agric. Food Chem. 45, (1997), 867–872) of the identification and characterization of volatile compounds from cocoa or chocolate products. The overall objective of the volatile mapping studies was to “compound” an intense artificial chocolate aroma with a high degree of flexibility so as to customize flavor profiles of chocolate or chocolate products. However, so far attempts to reconstitute the aroma of chocolate have not been successful. Although the synthetic mixtures obtained are reminiscent of chocolate, they lack the body and the intensity of a typical chocolate flavor.
At present, the currently available artificial chocolate flavors lack the desired intensity of chocolate aroma and an appropriate body. Consequently, a problem exists in that no means are known for artificially producing chocolate flavor that has all components of a typical chocolate aroma and an appropriate body. The present invention now seeks to overcome this problem.